This is a pair of triple neck ring decanters, finely cut all over, with umbrella type mushroom stoppers, circa.1930.

These look like they are circa.1815, but they are not even Edwardian. In the 1920s acid polishing was invented in England. Rather polishing on a wheel glass could be polished by dipping it in a vat of hydroflouric acid. The tell tale sign of this is that it take the edges of cut glass. It is why a lot of modern cut glass has a rather slick feel to it. These decanters have been acid polished, not too heavily, but they have. After WWII the fashion for this type of revival glass died and the labour cost of putting this much cutting (even with acid polishing) became prohibitive.

For all this they are still a fantastic pair of decanters, very skillfully, and probably really expensive when new.